Process for polymerization of a vinylidene monomer in the presence of a ceric salt and an organic reducing agent



PROCESS FOR POLYMERIZATION OF A VINYL- IDENE MONOMER IN THE PRESENCE OFA glRIC SALT AND AN ORGANIC REDUCING Guido Mino and Samuel Kaizerman,Plainlield, NJ.

No Drawing. Continuation of application Serial No. 628,212, December 14,1956, which is a continuation of application Serial No. 623,556,November 21, 1956. This application August 7, 1959, Serial No. 832,164

41 Claims. (Cl. 260--17.4)

This invention relates to a process for polymerizing a polymerizablemonomeric compound containing a polymerizably reactive CH =C group in anaqueous medium at a pH not greater than 3.5 in the presence of certainorganic reducing agents and a ceric salt which is soluble in at leastone component of the reaction medium. Still further, this inventionrelates to an aqueous solvent polymerization process wherein a vinyl orvinylidene monomer which is at least partially soluble in water ispolymerized in the presence of certain organic reducing agents and inthe presence of a ceric salt which is soluble is at least one componentof the reaction medium wherein the pH of the aqueous medium ismaintained at 3.5 or below. Still further, this invention relates to theprocess of polymerizing in an aqueous emulsion, a polymerizable vinyl orvinylidene monomer at a pH not greater than 3.5 in the presence of aceric salt which is soluble in at least one component of the reactionmedium and certain organic reducing agents. Still further, thisinvention relates to the polymerization products produced which comprisea substantially pure polymeric inter-reaction product of a polymerizablemonomer that contains a polymerizably reactive CH =C group and anorganic reducing agent which is capable of being oxidized by said cericsalt and which is capable of initiating the polymerization. Stillfurther, this invention relates to a process for preparing graftpolymers comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group in an aqueous medium ata pH not greater than 3.5 and in the presence of a polymeric organicreducing agent and a ceric salt which is soluble in at least onecomponent of the reaction medium.

One of the objects of the present invention is to polymerize avinylidene monomer in the presence of certain organic reducing agentsand a ceric salt that is soluble in at least one component of thereaction medium wherein pare graft polymers by polymerizing a vinylidenemonomer in the presence of a polymeric organic reducing agent which iscapable of entering into the reaction with and of initiating thepolymerization of said monomer as well as being capable of beingoxidized by ceric salts in an aqueous medium at a pH not greater. than3.5. These and other objects of the present invention willbe discussedin greater detail hereinbelow.

This application is a continuation application of our earlierapplications having the Serial Nos 623,556, filed November 21, 1956, and628,212, filed December 14, 1956, both now abandoned, entitledProcess'for PolymerizingVinylidene Monomer in the Presenceof a Ceric'322,768 Fat-tented Jan. 26, 1960 its Salt and an Organic Reducing Agentand the Product Thereby Obtained and Process for Polymerization and theProducts Produced Thereby, respectively. Each of these earlierapplications were continuation-in-part applications of our earlierapplication having the Serial No. 577,641, filed April 12, 1956, nowabandoned, entitled Process for Polymerization and the Products ProducedThereby, wherein we have disclosed a process for polymerizing vinyland/or vinylidene'monomers in the presence of certain reducing agentsand a ceric salt and the products produced through such a process.

In the practice of the process of the present invention, thepolymerization is carried out in aqueous solution or an aqueous emulsionas contrasted with other solvent polymerization processes such asorganic solvent polymerization or even bulk polymerization. Inasmuch asthe process of the present invention may be carried out in an aqueoussolvent medium or in an aqueous emulsion medium, it is immaterial as towhether or not the polymerizable monomeric vinylidene or vinyl compoundis water soluble. If the polymerizable material is completely watersoluble, one need not resort to use of an emulsion system. On the otherhand, if the polymerizable monomer is only partly soluble in water, onemay find that the polymerization can be carried out in an aqueoussolvent medium, Without benefit of an emulsifying agent, by means of adispersing agent or by use of a dispersing technique such as rapidagitation wherein the monomeric material, the reducing agent and theceric salt have ample opportunity ,to come into reactive contact withone another to produce the desired polymerization product. For monomericmaterials that are only slightly soluble in water or are substantiallycompletely, insoluble in water, the emulsion polymerization technique isrecommended.

In carrying out the process, it is imperative to use at least one of aclass of certain organic reducing agents as described brieflyhereinabove and discussed more fully hereinbelow and a ceric salt whichis soluble in at least one component of the reaction medium, namely, forinstance in the vinylidene monomer and/or the organic reducing agentand/ or wate Among the monomeric polymerizable compounds which may beused in the practice of the process of the present invention are thosecontaining a polymerizable CH =C group. This includes vinylidenecompounds and/ or vinyl compounds. More specifically, the followingpolymerizable monomers may be used: styrene, and substituted styrenessuch as ring-substituted and side chain substituted styrenes, e.g.,a-chlorostyrene, a-methylstyrene, and the like, o-methylstyrene,m-methylstyrene, p-methylstyrene, rene, 2,4,5-trimethylstyrene,p-ethylstyrene, o-bromostyrene, 2-bromo-4-ethylstyrene,p-isopropylstyrene, pchlorostyrene, 2,4-dichlorostyrene, orpolymerizable acrylic compounds, such as acrylic acid and its homologssuch as methacrylic acid, wmethacrylic acid, Ot-ChlOI'O- acrylicacid andthe like and derivatives thereof such as the anhydrides, amides, andnitriles, and the acrylic type acid esters of monohydric alcohols suchas the methyl, ethyl, propyl, butyl, isobutyl, amyl, hexyl, cyclohexyl,heptyl, octyl, decyl alcohols or the acrylic type acid esters of nitroalcohols such as 3-nitro-2-b utanol, 2-nitro-3-hexanol,Z-methyl-Z-nitro-l-butanol and Z-nitro- Z-met-hylpropyl alcohol, and theacrylic type acid esters of polyhydric alcohols such as ethylene glycol,diethor allyl or substituted allyl esters such as methallyl es-2,4-dimet-hylstyrene, 2,5-dimethylstyters. More specifically, one mayuse allyl acetate, allyl propionate, allyl chloroacetate, allylcaproate, allyl linoleate, allyl benzoate, methallyl acetate, the allylester of isobutyricacid, allyl acrylate, dialiyl carbonate, .diallyloxalate, diallyl phthalate, diallyl maleate, triallyl cyanurate and thelike. Still further, one may make use of the vinyl or vinylidene esterssuch as vinyl acetate, vinyl chloride, vinylidene chloride, vinylpropionate, vinyl butyrate, and the like. Vinyl ethers may also be usedsuch as vinylethylether, vinylpropylether, vinylisobutylether and p thelike or other vinyl compounds such as divinylsulfone,

divinylsulfide, vinyl pyridine and the like. Additionally, one may makeuse of the unsaturated polymerizable amides such as acrylamide,methacrylamide, ethacrylamide, methylene bisacrylamide and the like, orthe nitriles such as acrylonitrile, methacrylonitrile, ethacrylonitrile,alpha-chloro-acrylonitrile and the like. Whenever desirable, thesepolymerizable monomers may be used either singly or in combination withone another.

In the practice of the present invention, it is imperative that anorganic reducing agent be used which is capable of being oxidized by theeerie salt which is present in the system and which is capable ofinitiating the polymerization of the compound containing the CH C group.These reducing agents have been described in our earlier applications ascompounds containing the group wherein X is a member selected from thegroup consisting of OH, RCO, SH and NHR; wherein R is a member selectedfrom the group consisting of hydrogen, alkyl, aralkyl and aryl.Fundamentally, this description of the class of reducing agentsencompasses such classes of compounds as alcohols, or compoundscontaining an alcoholic hydroxy group, ketones, mercaptans, amines andthe like. Additionally, it was indicated that aldehydes could be used,as well as esters, amides, acetals and acids. Additionally, acidanhydrides may be used. The open bonds in the I compounds are organicresidues and/or in one instance only, hydrogen. Thus, for example, theymay be alkyl, both substituted and unsubstituted, aralkyl, bothsubstituted and unsubstituted and hydrogen or any combination of thesegroups. These organic groups or any combination thereof may besubstituted or unsubstituted and if substituted, may contain, forinstance, such substituent groups as nitro, amino, hydroxyl, carboxyl,carbonyl, halo, alkoxy, alkyl, amino, carboxy, sulfo, phospho andmercapto groups, individually, in plurality or admixtures thereof.

In our earlier application having the Serial No. 623,-

556, we have indicated that these organic reducing agents are monomericreducing agents as contrasted with the polymeric reducing agentsdisclosed and claimed in our .earlier application having the Serial No.628,212. The

thetic.

Some of the compounds suitable for use as reducing agents according tothe present invention are classed as monomeric reducing agents. Thesemonomeric reducing agents function to initiate polymerization and asconnecting links or members in the formation of linear oligo blockpolymers which are defined as' block copoly- 4 mers composed of a fewblocks in relatively long sequences having a degree of polymerizationequal to about 50 monomer units or more as opposed to conventional blockcopolymers which are formed of a number of relatively short sequencessuch as those having a degree of polymerization significantly less than50 monomet units, joined together through reactive end groups.

On the other hand, the remaining reducing agents used in the practice ofthe process of the present invention are classed as polymeric reducingagents, which term is intended to include dimers, trimers and higherpolymeric materials, both natural and synthetic, as indicatedhereinabove. These polymeric reducing agents are reactive in' the systemand become a part of the ultimate polymeric reaction product produced.These reducing agents will constitute backbones or blocks to which thevinylidene and/ or vinyl monomer used in the present invention arereadily attached to form graft copolymers or linear oligo blockcopolymers. By oligo block copolymers, as the term is used herein, ismeant block copolymers composed of a few blocks of relatively longsequences having a degree of polymerization equal to 50 monomer units ormore as opposed to conventional block copolymers formed of a largenumber of relatively short sequences having a degree of polymerizationof less than 50 monomer units joined together through reactive endgroups. Among the materials which are effective as preformed polymericreducing agents adapted for use as backbones or blocks in the formationof graft copolymers or'linear oligo block copolymers in accordance withthe present invention are compounds containing one or more alcoholichydroxy groups. Illustrative of this class of polymeric reducing agentsare polyvinyl alcohol, partial esters of polyvinyl alcohol, as forexample, formylated polyvinyl alcohol, acetylated polyvinyl alcohol,sulfated polyvinyl alcohol, nitrated polyvinyl alcohol, and the like;partial ethers of polyvinyl alcohol as cyanoethylated polyvinyl alcohol,celluose, including cotton, viscose, cuprammonium rayon, partial estersof cellulose such as cellulose acetate, cellulose propionate, celulosenitrate and the like; partial ethers of cellulose such as methylcellulose, ethyl cellulose, hydroxy ethyl cellulose, cyanoethylatedcellulose and the like; starch, partial ethers of starch, as forexample, cyanoethylated starch, partial esters of starch, as forexample, acetylated starch; poly ,B-hydroxy ethyl methacrylate andcopolymers thereof, and poly fi-hydroxy ethylacrylate and copolymersthereof and the like.

Among the monomeric alcohols which may be used in the practice of thepresent invention are the monohydric and polyhydric alcohols. Primary,secondary and tertiary alcohols may be used. More specifically, one canmake'use of methanol, ethanol, propanol, butanol, octadecanol,phenylethyl alcohol, phenylpropyl alcohol, chloro-phenylethyl alcohol,isopropanol, 1,3-dichoropropanol-Z, l-phenylpropauol-Z,l-(chlorophenyl)propanol-Z, or the glycols, such as ethylene glycol,diethylene glycol, propylene glycol, dipropylene glycol, trimethyleneglyco and other polyhydric alcohols such as glycerol, mannitol,

'Carbitol, pinacol, sorbitol and the alkandiols, such as-'1,4-butandiol, l,3-butandiol, 1,5-pentandiol, 2,3-pentandiol,1,3-pentandiol and alkoxy alcohols such as ethoxy ethanol ethoxypropanol, butoxy propanol, or aroxy alcohols such as phenoxy ethanol andthe like. Mono and diglycerides may additionally be used such as theglycerol invention are polyvinyl pyrrolidone, polymethylvinyl ketones,polyethylvinyl ketones, polypropylviuyl ketones ,hemiacetal, methylacetaldehyde .acetaldehyde hemiacetal, methyl butyraldehyde hemiacetal,propyl butyraldehyde hemiacetal and the like.

End copolyrners prepared by polymerizing alkyl vinyl ketones with otherpolymerizable materials such as those vinylidene and/ or vinyl monomersrecited hereinabove.

Among the monomeric mercaptaus that may be used as reducing agents inthe process of the present invention are methyl mercaptan, ethylmercaptan, n-propyl mercaptan, isopropyl mercaptan, Z-mercaptobutane,n-butyl mercaptan, n-decyl mercaptan, lauryl mercaptan, phenylethylmercaptan and the like. Furthermore, tertiary butyl, tertiary amyl,tertiary octyl mercaptan or the like may be employed. Examples of thepolymeric mercaptans which may be used in the practice of the process ofthe present invention are poly mercaptoethyl acrylate, polymercaptobutyl acrylate, poly mercaptoethyl methacrylate, polymercaptopropyl acrylate, poly mercaptopropyl methacrylate, and the likeor copolymers of mercapto ethyl acrylate, mercaptobutyl acrylate,mercaptoethyl methacrylate, mercaptopropyl acrylate, mercaptopropylmethacrylate and the like with other polymerizable materials containinga .polyrnerizable CH '"C group as recited hereinabove.

Among the monomeric amines which may be used as reducing agents in thepractice of the process of the present invention are methylamine,ethylamine, n-propylamine, n-butylamine, Z-phenylethylamine, and thelike. Polyamines may also be used such as ethylene diamine, trimethylenecliamine, diethylene triamine, tetraethylene pentamine, triethylenetetramine and the like. The polymeric amines used in the practice of theprocess of the present invention are the polyvinyl amines which can beprepared from polyacrylamide and from acrylamide copolymers by treatmentwith NaOCl by the Hoflman deg- 4 radation reaction.

The monomeric aldehydes may also be used as reducing agents includingsuch aldehydes such as formaldehyde,

acetaldehyde, propionaldehyde, butyraldehyde, phenyl propionaldehyde,heptaldehyde, and materials engendering monomeric aldehydes such astrioxymethylene, paraformaldehyde, and the like. Examples of thepolymeric aldehydes which may be used in the practice of the process ofthe present invention are homopolyrners such as polyacrolein, poly3-butenal, poly 3-pentenal, poly 5-chloro-3- pentenal and the like orcopolymers prepared by polymerizing acrolein, 3-butenal, 3-pentenal,S-chloro-S-pentenal and the like with other polymerizable materialscontaining the CH =C group such as those recited hereinabove.

The monomeric acetals may be used as reducing agents in the process ofthe present invention such as dimethyl acetal, diethyl acetal, dipropylacetal, formal, diethyl formal, dipropyl formal, dimethyl butyral,diethyl butyral and the like. Additionally, one may make use of thehemiacetals as the monomeric reducing agent such as methyl formaldehydehemiacetal, ethyl formaldehyde hemiacetal, propyl Among the polymericacetals which may be used in the practice of the process or" the presentinvention are polyvinyl formal, polyvinyl acetal, polyvinyl butyrfl, andthe vhke.

isosuccinate, propyl malonate, ethyl ethylmalonate are,

suitable. Furthermore, nitriles such as malononitrile,iso'succinonitrile, ethyl malononitriie, propyl malononitrile, isobutylmalononitrile may be employed. Various compounds which have more thanone'kind of activating group, such as, for example, cyanoacetic acid,alphacyanopropionic acid, methylcyanoacetate, ethyl cyanothesetemperatures.

=6 butyrate', cyanoacetamide, alpha :cyanopropionaniid; malonamic acidand the like may also be used.

Obviously, these monomeric reducing agents may be employed singly or incombination with one another.

Certain polymerizable monomers .contain the group as hereinabove definedand can, therefore, act as both reducing agent and monomer in thepolymerization reaction. Examples .of such compounds are allyl alcohol,methallyl alcohol, acrolein, fl-methacr olein, fl-hydroxyethyl acrylate,fl-hydroxyrnethacrylate, methyl vinyl ketone, ethyl vinyl ketone, propylvinyl ketone, and the like.

When the monomeric reducing agent is also a polymerizable material, itshould be difierent from the other polymerizable material containing theCH =C group. Otherwise, simple homopolymerization will take place whichis not within the purview of this invention. If the monomers aredifferent but each contains the group, rapid simple homopolymen'zationor copolymerization will occur. As a consequence, the poiymerizablemonomer containing the CH C group should be devoid of the X AH; 1

group and thelike as it is defined herein.

The reaction process of the present invention may be carried out attemperatures between about -S C. and 100 .C. but preferably attemperatures between about 10 C. and or C. Temperatures significantlyabove C. are to be avoided as a general rule because the redox systemsometimes decomposes too rapidly at The process of the present inventionmay be carried out under pressure or under partial vacuum but hispreferred to utilize atmospheric pressureinasrnuch as the reaction runsvery favorably at .thispressure.

The process of the present invention may be carried out at any pH valueup .toabout 3.5. Extremely lowpH values are operable as evidenced bypolymerization as shown in the subsequent examples. The pH value ismaintained between 1' and 2 in aqueous polymerization reactions foroptimum results. If the polymerization involves the use of .an emulsionsystem and a polymeric reducing agent, the pH valuecan'be ashigh as 6but still preferably below 3.5.

The amount of ceric compound which is utilized in the practice of theprocess ,of the presentinventionmay be varied over fairly wide limits.For example, one may utilize from about 10 to 10*. ,mol vlofce i i n permole of polymerizahle monomer. Preferably, one would use between 10- to10- mole of ceriqion per'mole of polymerizable monomer. ;Ceric;ion ispreferably introduced into the reaction mixture aecordingto the presentinvention in the form of ceric salt. Among the salts adapted for use inthe presentinvention are ceric nitrate, ceric sulfate, cericammonium'nit-rap e, eerie-ammonium sulfate, ceric ammoniumpyrophosphate, eerie iodate, ceric salts of organic acids,e,g.-,'cerium;naphthenate and cerium linoleate and the like. I-fhesecompounds may be p y singly or in cembinat o i h on another. Cericcompounds which are cap ble of forming ceric salts in situ under theacid gonditions ofzthepolymerization reaction such as ceric pxide,cerichydroxide and the like may beused. '7

In the practice-of the processpfi-gthe present invention, he a ousmulsia ttsslut ue szl fied a e l choose to make use of .an'emulsifyingagent of which there are many known in the art. Inasmuch as the processof the present invention including the aqueous emu1- sion processes arepreferably carried out at pH'values not greater than 3.5, it ispreferred to make use of those emulsifying agents which do not tend toprecipitate from an acid medium particularly, one within the pH range ofoperation. Among the emulsifying agents which may be used in the processof the present invention, are the sodium dialkyl sulfosuccinates such asthe sodium diisobutyl sulfosuccinate, sodium diamyl sulfosuccinate,sodium dihexyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodiumditridecyl sulfosuccinate and the like, or one may use the sodium alkyl,aryl sulfonates such as sodium octyl benzene sulfonate, sodium decylbenzene sulfonate, sodium isopropyl naphthalene 'sulfonate and the like.Additionally, one may use the sodium alkyl sulfates such as sodiumlauryl sulfate or sulfonated mineral oils may be used. The salts otherthan the sodium may be used; for instance, the potassium salts, thelithium salts and the like. Quite obviously, these emulsifying agentsmay be used either singly or in combination with one another. The amountof emulsifying agent used will depend in some measure on the degree ofwater insolubility of the components used in the reaction, namely thevinylidene monomer, the organic reducing agent and the ceric salt. Atany rate, the amounts conven tionally used as a range will find adequateapplication in the practice of the present invention.

In the practice of the present invention, one may make use of inorganicceric salts or organic ceric salts such as the oil soluble ceric salts.For the purposes of this invention, these oil soluble ceric salts may beformed in situ or they may be used as a preformed oil soluble cericsalt. In order to prepare these oil soluble ceric salts, one reacts aninorganic ceric salt such as ceric ammonium nitrate with an organicsulfur containing acid. These organic sulfur containing acids may beeither monobasic or polybasic, saturated or unsaturated, aliphatic oraromatic. Illustrative of these acids are the following: the mono anddisulfosuccinic acids, sulfochlorsuccinic acid, sulfoadipic acid,sulfopyrotartaric acid, sulfoglutaric acid, sulfosuberic acid,sulfosebacic acid, sulfomaleic acid, sulfofumaric acid, sulfodimethylsuccinic acid, sulfomethylgulutaric acid, sulfomalonic acid,sulfopropylsuccinic acid, sulfooctylglutaric acid, and the like. Stillfurther, the alkyl esters of these sulfocarboxylic acids such as themethyl, ethyl, propyl, butyl, amyl, hexyl, octyl esters and the like maybe used. Additionally, one may make use of the monoalkyl esters ofsulfuric acid such as monobutyl acid sulfate, monoamyl acid sulfate,monooctyl acid sulfate, monolauryl acid sulfate and the like..Additionally, one may make use of the alkyl benzene sulfona'tes such asthe octyl benzene sulfonate, nonyl benzene sulfonate, decyl benzenesulfonate, dodecyl benzene sulfonate, octadecyl benzene sulfonate,isopropyl naphthalene sulfonate and the like. These organicsulfur-containing acid materials are preferably used as alkali metalsalts in reaction with the ceric ammonium nitrate to form the organicoil soluble ceric salts. The preferred alkali metal is sodium althoughothers such as potassium, lithium and the like may be used.

Due to the characteristicsof the ceric ion, the ultimate oilsolubleceric product may be classed as a salt or as a complex.

- Among the oil soluble ceric salts which may be pro duced in accordancewith the process outlined hereinabove are ceric dihexyl sulfosuccinate,ceric dioctyl sulfosuccinate, ceric diheptyl s'ulfoglutarate, cericdidecyl sulfosuberate, ceric dilauryl sulfosebacate, ceric diamylsulfomaleate, ceric dimethyl sulfofuma rate, ceric dibutylsulfodimethylsuccinate, .ceric dilauryl sulfomethylglutarateand-comparable ceric salts'which can be produced by reacting any of thesodium salts of the organic sulfur 8 containin'g'acid ccmpoundslistedhereinabove with ceric ammonium nitrate.

In general, the time required to achieve a desired degree ofpolymerization may be determined empirically. Thus, for example, a givenpolymer may be precipitated at different time intervals and the extentof polymerization determined gravimetrically to determine the percent ofthe conversion of monomer to polymer. Where the amount of ceric ion andmonomer is known, suitable reaction times may be readily established toachieve the desired degree of polymerization. In addition, the ceric ionwhen being reduced undergoes a color change from yellow to brown to asubstantially colorless state, at which time it is substantiallycompletely reduced and will no longer eifectively initiatepolymerization. Thus, in an aqueous system, anoperator is readily ableto determine when the reaction has gone to substantial completion.

Should it be desirable to halt the reaction at any given time, whileceric ion is still present in the reaction mixture, this may be done bythe addition of hydroquinone, sodium sulfite or ferrous sulfate, whichmaterials exhaust the remaining ceric ion substantially instantaneously,thus halting the reaction. Furthermore, as an additional method ofhalting the reaction, the pH of the reaction mixture may'be adjusted tothe alkaline side, as for ex ample, to a pH of between 7 and 8, toprecipitate out the remaining portion of the ceric compound, prohibitingits further reduction, thus stopping the reaction.

The amount of reducing agent to monomeric material may be variedextensively depending on the properties of the ultimate product desired.As a consequence, large excesses of either material may be utilized inalternative reactions.

The organic reducing agent used in the present invention may be employedin amounts from 0.01% to 1000% based on the weight of monomer utilized.For non-polymeric reducing agents, otherwise referred to as monomericreducing agents, the amount may be varied from about 0.01% to based onthe weight of the monomer and preferably from about 0.1% and 10% basedon the weight of the monomer. The polymeric reducing agents may beemployed in amounts from 1% to 1000% or even more by Weight based on theweight of the monomer and preferably from about 10% to 300% by weightbased on the weight of the polymerizable monomer.

Referring now to the concept of grafting of polymer onto a preformedpolymeric backbone, the number of such grafts on a given backbone may becontrolled by controlling the amount of ceric ion added to the reactionmixture. Thus were a large amount of ceric ion to be added to a givenreaction mixture, instead of one such grafted side chain, a number ofsuch chains could be formed, theoretically, at least, at any point onthe backbone where the active group of the polymeric reducing agentidentified above is found. The length of the polymeric chain is afunction of the monomer concentration, ceric ion concentration,temperature and chain transfer constant of the backbone.

In order that the concept of the present invention may be more fullyunderstood, the following examples are set forth in which all parts areparts by weight unless otherwise indicated. These examples are set forthprimarily for the. purpose of illustration and any specific enumerationof detail contained therein should not be interpreted as a limitation ofthe case except as is indicated in the appended claims.

Example 1 Three S-part samples of acrylamide, recrystallized from ethylacetate, were dissolved in 50 parts of distilled water in screw capjars. To the first and second samples were added 0.25 and 0.2 part ofmannitol, respectively. In the third sample, no reducing agent waspresent. To each sample was then added 2x10- mole ofceric' am- 9 fnoniumnitrate as an 0.1 N-aqueous solution of ceric ammonium nitrate in molarnitric acid. The solutions were flushed with carbon dioxide andpolymerized at 25 C. for 1 hour. The results obtained are set forth inthe table below:

Ceric Nitrate, Moles Mmitol, Time, Percent parts Minutes Conversion2X10- 60 5 2X10 0.25 60 92 2Xl0' 0. 20 60 91 it can readily be seen thatthe absence of mannitol in the polymerization system at room temperatureresulted in a negligible conversion of monomer to polymer.

Example 2 Seven samples of acrylonitrile, purified by steam distillationover 5% phosphoric acid and dried over sodium sulfate were dissolved indistilled water in 7 suitable reaction vessels. Ceric ammonium nitrate,organic reducing agents (specified below) and nitric acid in an amountsutlicient to adjust the pH to 1.5 where then added in proportions setforth in the table below. These solutions were then flushed with carbondioxide and polymerized at 25 C.

Ceric Acrylo- Conver- Ammonium Reducing Agent nitrile, Water, Time,sion,

Nitrate, Parts Parts Parts in. Percent Moles 2.5 50 60 10 2.5 50 60 382.5 50 60 70 2.5 50 60 70 2X10 None 20 400 30 0 2 10-0.651.3-dichloro-2- 20 400 30 80 propanol. 2X10- 0.261.3dicbloro-2- 20 245 94 propanol.

The results indicate that mannitol, ethanol and dichloro propanolincreases the percent of conversion of monomer to polymer in the systemhere illustrated. Ace-tone, it will be observed, was somewhat lesseffective.

Example 3 Example 4 Into a suitable reaction vessel containing 100 partsof water at C., there is introduced 5 parts of methylacrylate and 0.5part of propionaldehyde. Stirring accomplishes solution. The solution isthen flushed with carbon dioxide after which 4 parts of 0.1 N solutionof ceric ammonium nitrate in molar nitric acid are added. Polymerizationstarts immediately with polymeric material precipitating as a rubberymass. The yield of polymer after 30 minutes of reaction is 3.6 partsrepresenting a conversion of about 72%.

Example 5 A solution of 1.5 parts of acrylonitrile and 0.1part ofmalonic acid in 25 parts of water are introduced into a suitablereaction vessel and the solution is flushed with carbon dioxide and thencooled to about 5 C. To this solution there is added 1.5 parts of 0.1 Nsolution of ceric ammonium sulfate in lNsulfuric acid. After about- 1045 minutes, the yield of polymer is 1.18 parts which rep resents aconversion of about 79%.

Example 6 Into a suitable reaction vessel, there is introduced 6 partsof acrylonitrile and 0.5 part of tertiary butyl mercaptan together with100 parts of water at 25 C. The mixture was stirred thoroughly toaccomplish solution and after flushing the same with carbon dioxide, 5parts of 0.1 N solution of ceric ammonium nitrate in molar nitric acidare added. Polymerization started within about 2 minutes. After aboutone hour, the polymer slurry is dispersed in 200 parts of water and thepolymer is separated by filtration. The yield is about 4.85 parts whichrepresents a conversion of about 81%.

Example 7 Into a suitable reaction vessel containing 50 parts of water,there is introduced 3.5 parts of acrylonitrile and 0.3 part ofn-butylamine. The pH of the solution is adjusted to 1.5 with nitricacid. After flushing the reaction zone with nitrogen, 0.1 part of cericammonium. nitrate is added. The polymerization started in about. oneminute and after 45 minutes at room temperature,. the yield of polymeris 2.66 parts representing a con version of about 76%. The polymer issoluble in dimethylformamide and dimethylsulfoxide.

Example 8 A solution of 1.5 parts of acrylonitrile and 0.1 part: ofdiethyl malonate and 25 parts of water was flushed. with carbon dioxideand cooled to 20 C. To thisv solution, 1.5 parts of 0.1 N solution ofceric ammonium: nitrate and N nitric acid were added. After 45 minutes,a high yield of polymer was obtained.

Example 9 A solution of 3.0 parts of acrylonitrile and 0.2 part? ofmalonamide and 50 parts of Water was flushed with. carbon dioxide andcooled to 5 C. To this solution, 3.0 parts of 0.1 N solution of cericammonium sulfate: and N sulfuric acid were added. After 45 minutes, a;high yield of polymer was obtained.

Example 10 A solution of 4.5 parts of acrylonitrile and 0.3 part." ofmalonic acid and parts of water was flushed with.- carbon dioxide andcooled to 5 C. To this solution... 4.5 parts of 0.1 N solution of cericammonium sulfate: and N sulfuric acid were added. After 45 minutes,ahigh yield of polymer was obtained.

Example 11 A solution of 1.5 parts of acrylonitrile and 0.1 part: ofmalononitrile and 25 parts of water was flushed with carbon dioxide andcooled to 5 C. To this, 1.5 parts of 0.1 N solution of ceric ammoniumsulfate and N sul-- furic acid were added. After 45 minutes, a highyield of polymer was obtained.

Example 12 Into a suitable reaction vessel, there is introduced 7'"parts of acrylonitrile and 0.5 part of pinacol hydrate, dissolved inparts of water maintained at 20" C. There is then added 4 parts of a 0.1N solution of ceric am Into a suitable reaction vessel, there isintroduced parts of methyl acrylate dissolved in 220 parts of water.There is then added 1.5 parts of a 35% aqueous solution of'formaldehyde. After flushing with carbon dioxide, there is added 8 partsof a 0.1 N solution of ceric ammonium nitrate in molar nitric acid.After about 1 hour at 5- C., there is produced a rubbery polymer in ayield of 8.2 parts.

" Example Into a suitable reaction vessel, there is introduced 6 partsof acrylonitrile dissolved in 100 parts of water and there is thenadded.0.5 part of dibutyl acetal. The solution is flushed with nitrogenand there is then added 4 parts of a 0.1 N solution of ceric ammoniumnitrate in molar nitric acid. The polymerization began within threeminutes and after 90 minutes at C., the yield of polymer was 4.45 parts.

Example 16 of ceric ammonium nitrate are added. The polymerization beganwithin 2 minutes and after 90 minutes, the yield of polymer was 4.0parts which represents a conversion of 89%.

Example 17 Into a suitable reaction vessel, there is introduced 15 partsof purified acrylamide in 200 parts of oxygen-free Water to which thereis then added 1.5 parts of acetaldehyde. The solution is cooled to 15 C.and flushed briefly with carbon dioxide after which there is added 6parts of a 0.1 N solution of ceric ammonium nitrate in molar nitricacid. After 80 minutes, the solution is poured into an excess ofmethanol in order to precipitate the polymer. The yield ofpolyacrylamide is 6.1 parts. The polymer contained aldehyde end groupsand was suitable for use in the preparation of block polymers byreaction with a second polymerizable monomeric material using additionalceric ion.

Example 18 Into a suitable reaction vessel equipped with thermometerand,stirrer,.there is introduced 100 parts of Water, 2 parts of sodiumdihexyl sulfosuccinate, 50 parts of styrene and 1 part ofethylacetoacetate. The air in the reaction vessel is displaced withnitrogen. After .the reaction mixture is substantially completelyemulsified by stirring, there is added 2 parts of a 0.1 N solution ofceric ammonium sulfate in N sulfuric acid. Polymerization-is'carried outfor a period of about 4 hours at 40,

C. Thereafter, the resulting latex is coagulated in an excess of :50ethanol-acetone mixture. The yield of polymer is 345 parts.

4 Example 20 Into 'a suitable reaction vessel equipped as in thepreceding exampldthere is introduced a mixture of 75 parts 12 of water,21 parts of chloroprene, 1.5 parts of sodium dihexyl sulfosuccinate and1 part of propylene glycol, the mixture is emulsified by stirring. Afterdisplacing the air in the vessel with nitrogen, there is added 2 partsof a 0.1 N solution of ceric ammonium sulfate in N surfuric acid.Polymerization is allowed to proceed for 1 hour at 30 C. The resultinglatex is coagulated in an excess of a 75:25 methanol-acetone mixture andthe polymeric material is separated by filtration. The polymer yield is17.8 parts.

Example 21 Five parts of acrylarnide were added to 100 parts of watercontaining 5 parts of polyvinyl alcohol (Elvanol 51.05, a commerciallyavailable polyvinyl alcohol having a number average molecular weight of10,000) in a screw cap jar. The solution was then flushed with carbondioxide and 4 parts of 0.1 N-aqueous ceric ammonium nitrate and 4 partsof molar nitric acid were then added. Polymerization was carried out atroom temperature (25 C.) for 45 minutes and then the polymer wasprecipitated by pouring the reaction mixture into an excess of acetone.After drying for 16 hours at C. in vacuo, a yield of 8.99 parts wasobtained which was equivalent to a 79.8% conversion.

Fractional precipitation of the graft copolymer in a 50:50 by volumemethanol-water system was achieved by incremental additions of acetone.This procedure yielded sharp fractions containing from 57 to 60% ofpolyacrylamide to 43 to 40% of polyvinyl alcohol and some free polyvinylalcohol. No polyacrylamicle was to be obtained.

Example 22 Five parts of methyl acrylate, inhibitor free, were added toparts of distilled water containing 5 parts of polyvinyl alcohol(Elvanol 51.05 To this solution 10 parts of 0.1 N-aqueous ceric ammoniumnitrate containing 1 part of molar nitric acid was added. The reactioncontainer was flushed with carbon dioxide and the polymerization wascarried out at room temperature for 75 minutes.

The resulting latex was poured into an excess of 1:4 hexane-ethanolsolution to precipitate the graft polymer. Thereafter, the graft polymerwas filtered and dried at 50 C. in vacuo for 16 hours. The yield ofgraft polymer was 9.62 parts and represented a conversion of 92.4%.

The graft polymer was insoluble in acetone and in benzene, although itswelled in both solvents.

The graft copolymer was not cross-linked because acetylation in amixture of acetic acid and acetic anhydride at 60 C. brought it intosolution. The acetylated graft copolymer was soluble in acetone.

Two parts of the resulting graft polymer upon extraction for 4 hourswith boiling acetone suffered a loss in weight of 0.04 part. Furtherextraction in boiling acetone for 20 hours caused an additional loss inweight of 0.015 part.

The grafting efiiciency of the system, as defined above, was determinedby dividing the amount of polymethyl acrylate which was insoluble by thetotal amount. present before extraction. Assuming that the graft iscompletely insoluble in acetone and that the polymer extracted is purepolymethyl acrylate, the efficiency of the illustrated graftcopolymerization of this system was 97%. To further illustrate thedifference between graft copolymers and mechanical mixtures, amechanical mixture containing 1 part of polymethyl acrylate and 1 partof polyvinyl alcohol was extracted for 4 hours in boiling acetone. Underthese conditions, 98% of the polymethyl acrylate was extracted.

acid, dried over sodium sulfate and distilled under nitrogen. Threesamples of the sizes represented in the table below were then added toaqueous solutions containing the reducing agents set forth in the tablebelow in the proportions reported therein. Ceric ammonium nitrate andnitric acid were then added. The solutions were flushed with carbondioxide and then polymerized at room temperature for the required periodof time.

Ceric Reducing Agent, Acrylo- Water, Time, Percent Nitrate, Partsnitrile, Parts pH Min. Conv.

Moles Parts 6X10-* 2 PVA 1 2 5 50 1 45 85.3 2X10' 0.5 PVA 9 5 200 1.5120 73.8 1X10- 0.5 Methoccl 9 5 200 1 105 70.1

1 Polyvinyl alcohol, Elvanol 51.05. 2 Methocel (a commercially availablemethyl cellulose havmg an absolute viscosity of cps. and a methoxycontent 01' 27.5 to 32.0%).

These graft copolymers are insoluble in dimethyl formamide, ethylenecarbonate, and concentrated solutions of potassium thiocyanate. Thegraft copolymers swell up to 100 times their original volume when heatedin the presence of dimethyl formamide but when extracted with dimethylformamide in a Soxhlet extractor for 24 hours only a very small amountof polyacrylonitrile was found in the solvent.

Example 24 The mixture was diluted with 50 parts of water and acidifiedto pH 1.5 with N-nitric acid and 2x10 moles of ceric ammonium nitratewere added. Polymerization was carried out at room temperature for 30minutes. The graft copolymer was filtered and dried in vacuo at 70 C. toyield 5.5 parts of graft copolymer.

The graft was soluble in 60% (by weight) of potassium thiocyanatesolution.

Example 25 Five parts of polyvinyl alcohol were dissolved in 100 partsof water in a three-neck flask fitted with nitrogen inlet, stirrer andcondenser. To this solution was added 22.5 parts of styrene and 5 partsof 0.1 N-ceric sulfate in 1 N-sulfuric acid. The solution was stirred at40 C. for minutes and then 1 part of Aerosol MA (a sodium dihexylsulfo-succinate) was added.

Polymerization was carried out for 5 hours at C. The latex wascoagulated by pouring into acetone and the polymer was filtered anddried. The total yield of polymer was 22 parts. The polystyrene graft onpolyvinyl alcohol was insoluble in benzene.

While the above examples deal generally with the initiation ofpolymerization and a process for producing graft copolymers and thelike, a particularly advantageous facet of the present invention is theapplication of its principles to a system in which cellulosic materialsfunction as what has been hereinabove referred to as the polymericreducing agent.

By cellulosic materials hereinabove referred to, fibers, fabrics orpaper or other materials composed of cotton, linen, viscose, rayon,wood, paper, pulp or the like, or mixtures or blends thereof areintended to be included.

Although the polymerization of olefinic monomers within the fibers ofcellulosic materialshas been disclosed heretofore, the methods used haveseveral limitations. The most-serious of these is the simultaneouspolymerization of monomers in the treatment bath and on the surface ofthe cellulosic material, as well as within the fibers of the material.This results in a waste of monomer as well as an objectionable layer ofpolymer on the surface of the material which is often difficult toremove. A distinct advantage of this invention is that polymerizationcan be made to occur substantially entirely within the fibers of thecellulosic material. In addition, the polymer thus deposited is graftedto the cellulose molecules and becomes an integral part of the material.

The following examples are given as a means of illustrating this aspectof the present invention.

Example 26 Five samples of x 80 cotton percale were treated with aqueoussolutions containing varying concentrations of acrylonitrile, cericammonium nitrate, and nitric acid. The liquor to fabric ratio was atleast 30:1 and the temperature was 30 C. in all instances. Uponcompletion of the treatment, the fabric was thoroughly washed in Asample of viscose rayon challis, weighing 6.71 parts was treated with 12parts of acrylonitrile, 15 parts of 0.1 molar ceric ammonium nitrate,13.5 parts of 1.0 N nitric acid and 256 parts of water for 30 minutes at30 C. The solution was flushed with carbon dioxide to render itoxygen-free.

The fabric was thoroughly washed after treatment and then dried at 107C. for 10 minutes prior to weighing. After treatment, washing anddrying, the fabric weighed 8.93 parts, indicating a weight increase of33.1%

Example 28 Four samples of'v 80 x 80 cotton percale were treated withaqueous solutions containing varying concentrations of acrylamide andfixed concentrations of ceric ion as ceric ammonium nitrate and fixedconcentrations of nitric acid, the composition and concentration ofthe-components being given in the table set forth hereinbelow; Theliquor to. fabric ratio was at least 30:1 and the treatment wascontinued for 30 minutes at 30 C. in all instances. A carbon dioxideatmosphere was maintained over the polymerization bath at all times torender is oxygen-free. Upon completion of the treatment, the fabirc wasthoroughly washed in several changes of water to insure complete removalof nitric acid before drying. The fabric samples were then dried for 10minutes at 107 C. before weighing.

Acrylamide Oon- Ceric Ion Nitric Acid Time of Weight Incentration, Per-Ooncen- Concen- Treatment crease of cent tration tration (minutes)Fabric, (molar) (Normal) Percent Example 29 A sample of 80x 80 cottonpercale, weighing 6.26 parts was treated with a solution containing 10parts of methyl acrylate, 2.5 parts of a 0.1 molar ceric ammoniumnitrate in 1.0 N HNO 10 parts of 1.0 N nitric acid and 225 parts -'ofwater for 30 minutes at 25 C. A carbon dioxide atmosphere was maintainedover the polymerization bath.

The final weight of the fabric was 11.85 parts, corresponding to aweight increase of about 88% Example 30 A sample of viscose rayonchallis, weighing 6.73 parts was treated with a solution consisting ofparts of methylene bis acrylamide, 5 parts of 0.1 molar ceric ammoniumnitrate in 1 N HNO parts of l N nitric acid and 230 parts of water for30 minutes at 30 C. Atmosphere of carbon dioxide was maintained over thepolymerization bath.

The final weight of the fabric was 7.71 parts, indicating a weightincrease of 14.5%.

Example 31 A sample of 80 x 80 cotton percale was treated according tothe procedure described in Example 28 (Sample 2) to depositpolyacrylamide within the fiber of the fabric. The polymer deposit wasequal to 7% of the initial weight of the material. The fabric was thentreated for 10minutes with a 37% formalin solution at 85 C. and at aliquor to cloth ratio of 7:1.

After thorough washing to remove excess formaldehyde, and subsequentdrying, the fabric was padded through a 3% solution of magnesiumchloride catalyst, and then heated to 175 C. for 100 seconds. Thewrinkle recovery as determined by the Monsanto wrinkle recovery testmethod of the treated fabric was 262 compared to 142- for the untreated.The treatment resulted in a tensile strength loss of 32%.

A wrinkle recovery of 250 can be obtained by treating cotton withformaldehyde alone under acid conditions. The tensile strength loss ofthe treated fabric, however, is of the order of 70% that of anuntreatedfabric.

' Example 32 A sample of cellulosic filter paper was treated for 5minutes at 30 C. with a 7% solution of acrylonitrile, 0.005 molarconcentration of ceric ion as ceric ammonium nitrate, and 0.05 N nitricacid solution. The solution was flushed with carbon dioxide to renderoxygen-free. Thereafter, the sample of filter paper was thoroughlywashed with water. and dried to give a weight increase of 45% Thetreated paper was cut into small fragments and treated with 200 timesits weightof 1.0 molar cupriethylone diamine solution for hours at roomtemperature.

The paper was largely unafifected by the reagent and after washing anddrying was found to have lost less than 5% of its weight. The untreatedpaper subjected to thesame solvent action was completely dissolved inless than 6' hours. I 1 a The treated paper was thenlextracted withdimethyl formamideat temperatures of between 70 and 80 C. for 16 hours.The dimetihyl formamide remained perfectly clear upon dilution withwater, indicating that no free polyacrylonitrile was extracted. v q

The treated paper showed outstanding resistance to acid and alkalidegradation. A sample of paper was immersed for 8 hours in concentratedhydrochloric acid and did not disaggregate or lose its strength. Asimilar sample remained unchanged when treated' for 8 hours with 4%sodium hydroxide at 80 C.

Identical paper samples which have not been treated according to theprocess set forth above has a tensile strength of 10 pounds when dry.and 0 when wet; while paper so treated has a tensile strength of 34pounds when dry and 28 pounds when wet.

Exam l Five parts of Carbowax 6000.(. a commercially availablepolyethylene glycol having a molecular weight of imines are alsosatisfactory for the preparation about 6,000) was dissolved in 100 partsof water contain.-

ing 5 parts of acrylonitrile. To this solution was added 8X10- mole ofceric ammonium nitrate and sufiicient nitric acid to adjust the pH to 1.The solution was flushed with carbon dioxide and polymerized for 145minutes at room temperature. The resulting polymer was coagulated,filtered and extracted twice with water at reflux for five hours. Theresulting oligo block copolymer contained 89.2% of acrylonitrile and10.8% Carbowax 6000.

This example is illustrative of an oligo block copolymer in which thepreformed polymeric reducing agent (polyethylene glycol) andacrylonitrile are reacted in the presence of a ceric compound.Copolymers of this type may be spun from aqueous potassium thiocyanateand used in the preparation of synthetic fibers.

Example 34 15 parts of acrylonitrile and 5 parts of polyvinylamine,prepared from polyacrylamide by Hoffman degradation, were dissolved in300 parts of water at 25 C. After flushing with nitrogen, the solutionwas acidified to pH 1.5 with. nitric acid and 0.6 part of ceric ammoniumnitratewas added. Polymerization started within one minute. Afterminutes, the polymer dispersion was poured into an excess of acetone andthe graft polymer separated by filtration; The yield was 17 parts andrepresented a conversion of the acrylonitrile.

Example 35 A mixture of 100 parts of water, 5 parts of Aerosol MA, 40parts of styrene and 10 parts of acrolein was emulsified by stirring ina suitable reaction vessel. After displacing the air in the vessel withnitrogen, 0.2 part of potassium persulfate was added. Polymerization wascarried out for 3.5 hours at 50 C. at which time the conversion ofmonomer to polymer was approximately The latex, after stripping theexcess monomer under vacuum, contained 23% of styrene-acroleincopolymer.

80 parts of the above latex was diluted with 80 parts of water in areaction vessel equipped with a mechanical stirrer. A solution of 0.5part of ceric dihexyl sulfosuccinate in 25 parts of ethyl acrylate wasadded to the emulsion at 30 C. over a period of 1 hour. Upon completionof the addition, the temperature of the reaction mixture was raised to40 C. and maintained at that temperature for 5 hours. The latex wascoagulated with methanol to give 36 parts of graft copolymer, whichrepresented a 70% conversion of the ethyl acrylate.

Example 36 I A solution of 1 part of polyvinyl pyrrolidone and 6.5 partsof acrylonitrile in parts of water wasflushed with nitrogen and cooledto 20 C. Two parts of an 0.1 N solution of ceric ammonium nitrate inmolar nitric acid were added. Polymerization started immediately. After.two hours, the mixture was slurried with 200 parts of acetone and thepolymer separated by filtration. The yield was 6.05 part and representeda conversion of 77.5%.

Materials most suitable for the preparation of linear oligoblock'copolymers are those having a central organic chain which hasfunctional terminal groups such as hydroxy, mercapto, aldehydic,-amino,'keto, acetal groups, as ffor example, polyethylene glycol, beinggenerically written as HOC H O(CH O), C H OH, wherein n is 0 or apositive integer. These compounds range in molecular weight from'a'fewhundred to many thousands,- as for example, 4,000 and 6,000or more. Inaddition to the above-mentioned materials, the polyethylene ofthe linearoligo block copolymer. I

1 While thedetailed mechanism by which-the process of this inventionoperates and the resulting advantages that areproducedjateznotfully'known,.the ceric ion redox system initiates:polymerization of suitableunsaturated.

17 monomers through a free radical mechanism according to the followinggeneral formula where the polymeric reducing agent is a polymericalcohol:

wherein H O(l3 is the free radical capable of reacting with suitableunsaturated monomers. The oxidation reaction proceeds through a singleelectron transfer mechanism, the reducing agent donatingone electron tothe oxidizing agent and the free radical being located on the polymericorganic reducing agent. This is important in that it initiatespolymerization on a given reducing agent, i.e., a preformed polymericchain material, at the situs of the carbon atoms having the freeradicals thereon, which is believed to be the carbon atom in the grouphereinabove described. The grafted polymer chain is thus attached to thereducing agent through a carbon linkage, i.e., the polymer P, isattached to the central organic chain as Polymerization of unsaturatedmonomers in the presence of ceric ion and performed polymer chains orbackbones such as cellulose, starch, polyvinyl alcohol, which maycontain a multiplicity of groups and may therefore be termedpolyfunctional reducing agents, are believed to produce graft copolymersaccording to the following equations:

The free radical on the preformed polymer chain (reducing agent) is thenbelieved to react with a given monomer (M) to produce a graft copolymeras follows:

Graft copolymers may, of course, be prepared by conventional methodswhich take advantage of the chain transfer reaction between growingpolymer chains and the backbone. However, the yields of graft copolymersobtained are low and are a function of the degree of conversion. Othermethods take advantage of catalysts like persulfates and peroxides,which under certain conditions may attack the backbone to produce freeradicals. In these cases, however, a mixture of homopolymers and graftcopolymers are obtained, because conventional initiators activate themonomer as well as the backbone.

With ceric salts in the redox system of the present invention, the graftcopolymers are substantially free of homopolymers, because the backbonesare attacked very rapidly at relatively low temperatures, while themonomers are not.

Heretofore, it has been considered impossible to prepare graftcopolymers essentially free of homopolymers a 5050 graft copolymer ofpolyvinyl alcohol and polyeven with elaborate and impractical processes.The process described herein give graft copolymers essentially free ofhomopolymers as one of its major advantages. That is, by this process asubstantially pure graft copolymer may be produced.

The advantages of graft copolymers over mixed copolymers is well known.For example, the solvent resistance of graft copolymers is much improvedover that of mixtures of polymers. As is shown in Example 32 above, thegrafted copolymer of acrylonitrile on cellulose is insoluble in thesolvents for either polyacrylonitrile or for cellulose.

The absence of free backbone polymer in the polymerization product canbe assured by incorporating sufficient ceric salt in the reactionmixture to give at least one reactive site on each backbone molecule.Obviously, the higher the molecular weight of the backbone polymer, theless ceric salt will be required to give this one reactive site permolecule.

It can readily be seen that the properties of a backbone may be readilyand widely varied by employing the process of the present invention.Three types of graft copolymers may be made by this method. First, ahomopolymer chain may be grafted to a backbone in accordance with thefollowing general formula wherein A represents a given backbone and B apolymer chain grafted thereon:

Thirdly, a copolymer chain can be grafted onto a given back-bone, whentwo suitable monomers are utilized in accordance with the followinggeneral formula wherein A represents a given backbone and BCB-- a givencopolymer. In this instance, C may be a monomer which cannothomopolymerize.

By proper selection of monomer or monomers, melting point temperatures,water-proofing characteristics and moldability of a polymer may besuitably modified.

The next example illustrates how a monomeric material can be graftedonto a graft copolymer.

Example 37 Into a suitable reaction vessel containing 2.4 parts ofacrylamide, there is added 4.8 parts of methyl acrylate. The solution isflushed with carbon dioxide and then 4 parts of 0.1 N ceric ammoniumnitrate in 0.1 N nitric acid are added. The polymerization is carriedout for about 1. hour at room temperature (25 'C.). The result- .ingpolymeric material is precipitated in an excess of methanol, filteredand dried in vacuo at 50 C. The total Example 38 Into a suitablereaction vessel containing parts of polyvinyl alcohol (Elvanol 51.05)dissolved in 100 pants of'distilled water, there is added 5 parts ofacrylamide,

5 parts of methyl acrylate and 4 parts of 0.1 N ceric ammonium nitratein 1.0 N nitric acid. Copolymerization is carried out for 20 minutes atroom temperature. The resulting suspension is precipitated with anexcess of ethanol. The graft copolymer thus produced is filtered anddried in vacuo at 70 C. The total yield is 14.8 parts.v The graftcopolymer thus produced is insoluble in acetone but is easilydispersible in water.

Several methods of preparation of block copolymers have been describedheretofore. Their synthesis requires the preparation of individual blockpolymers containing reactive groups at both ends and a subsequentjoining of these bloc-ks through a second step. Most second stepsinvolve the condensation of these preformed blocks 'When unsaturatedmonomers are polymerized in the presence of ceric ions and suitablereducing agents, such as trimethylene glycol,1,4-butandiol and the likepolymer molecules containing hydroxyl groups on one or both ends,depending upon the termination reaction, are believed to be formed.These polymers can then be reacted further as a polymeric reducing agentwith another monomer in the presence of ceric ions to produce acopolymer consisting of a few long sequences of the two monomers. Theselinear oligoblock copolymersare substantially different from theblockcopolymers previously described because the physical properties of ablock copolymer. are a function of the length and number of sequences.

Copolymers prepared from hydrophobic and hydrophilic blocks showpeculiar solubility characteristics and can be used as surface activeagents. Graft copolymers can also be used as adhesives and bondingagents for nonwoven fabrics and for pigments.

asaarss -20 or to impart new properties thereto. With regard to textilesand textile 'r'riaterials, in a'ddition to providing a means ofpreparing more durable finishes and new finishes :for fabrics, fibersand fabric may be rendered more resistant to fire, shrinkage, rot,acids, mildew, and the like. In addition, their tensile strength andwrinkle resistance, and the like, may be improved.

With suitable reducing agents, new classes of surface active agents maybe readily prepared. Thus, for example, polymers possessing hydrophiliccharacteristics may be readily grafted onto a suitable backbone, as forexample, at a second point thereon. In addition, new lubricating oiladditives may be developed and properties of existing ones improved. Inmany instances, the polymerization products of the present invention maybe further coreacted with various resins, including amino resins, suchas urea-formaldehyde condensates, triazine formaldehyde condensates ofvarious ethylene ureas, or the alkylated derivatives of these materialsto achieve a wide variety of desired end properties, particularly in thefields of textile and paper chemistry.

The above-enumerated potential uses of the concepts of the presentinvention are only a relatively few of the many which will readily occurto those skilled in various ants.

We claim:

1.. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group in an aqueous medium ata pH not greater than 3.5 in the presence of a ceric salt which It willbe noted in the above examples, and particularly with regard to Examples27-33 relative to the graft polymerization of suitable monomers on thecellulosic backbones of materials such as cotton fabric, regeneratedcellulose fabric, viscose rayon fabric, paper, paper pulp, wood, woodpulp, and the like, that certain advantages of the present process,namely its ability to operate at low temperatures, and more specificallyroom temperature, and the fact that excessive loss of monomer due 'tohomo polymerization in the bath are obviated. This is particularlyevident with regard to Example 33, wherein the graft polymer wasinsoluble in both cupridiethylene diamine and dimethyl foramide,indicating that the cellulose molecule was modified and that no freepolyacrylonitrile was present. This is believed to indicate clearly thatthe polyacrylonitrile is grafted onto the cellulosic backbones of thematerial. I

By employing the process of the present invention, wherein the reducingagent is cellulose or cellulosic materials, the proper-ties of saidmaterials may be varied to impart greater utility heretoforeunobtainable. By the process of the present invention, new finishes forfibers may be obtained, dyes and finishes may be rendered more durableon both fabric and paper. Surface characteristics,

of metals may be modified, now rubber-soluble polymers may be produced,new modifiers, additives and plasticizers for plastics and resins may beproduced. Pigment of improved bleed resistance and new pigment bondingagents may be produced. Protein and proteinaceous materials may bemodified to improve existing properties medium,a"ud anorganic reducingagent which is capable of being oxidized by said ceric salt and which iscapable of initiating the polymerization, wherein the only reducingagent is an organic reducing agent.

2. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group in an aqueous medium ata pH not greater than 3.5 in the presence of a ceric salt which issoluble in at least one component of the reaction medium, and amonomeric organic reducing agent which is capable of being oxidized bysaid ceric salt and which is capable of initiating the polymerization,wherein the only reducing agent is anorganic reducing agent.

3. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group dissolved at leastpartially in an aqueous medium at a pH not greater than 3.5 in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium, and a monomeric organic reducing agent which iscapable of being oximonomeric compound containing a polymerizablyreactive CH =C group dissolved at least partially in an aqueous mediumat a pH not greater than 3.5 and in the presence of a ceric salt whichis soluble in at least one component of the reaction medium, and amonomeric aldehyde which is capable of being oxidized by said ceric saltand which is capable of initiating the polymerization wherein saidaldehyde is the sole reducing agent.

5 A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group dissolved at leastpartially in an aqueous medium at a pH not greater than 3.5 and in thepresence of a ceric salt which is soluble in at least one component ofthe'reaction medium, and monomeric acetaldehyde wherein saidacetaldehyde is the sole re ducing agent.

6. A process comprising polymerizing acrylamide dissolved in an aqueousmedium at a pH not greater than 3.5 and theprfi fi iw 9i 1a ceric saltwhich is soluble u .-...pp

21 in at least one component of the reaction medium and acetaldehydewherein said acetaldehyde is the sole reducing agent.

7. A process comprising polymerizing acrylamide dissolved in an aqueousmedium at a pH not greater than 3.5 and in the presence of a ceric saltwhichis soluble in at least one component of the reaction medium andmonomeric acetaldehyde, as an organic reducing agent, wherein the onlyreducing agent is an organic reducing agent.

8. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group dissolved at leastpartially in an aqueous medium at a pH not greater than 3.5 and in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium, and a monomeric mercaptan which is capable of beingoxidized by said ceric salt and which is capable of initiating thepolymerization wherein said mercaptan is the sole reducing agent.

9. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group dissolved at leastpartially in an aqueous medium at a pH not greater than 3.5 and in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium and tertiary butyl mercaptan wherein said mercaptanis the sole reducing agent.

10. A process comprising polymerizing methyl acrylate dissolved in anaqueous medium at a pH not greater than 3.5 and in the presence of aceric salt which is soluble in at least one component of the reactionmedium and tertiary butyl mercaptan wherein said mercaptan is the solereducing agent.

11. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group dissolved at leastpartially in an aqueous medium at a pH not gretaer than 3.5 and in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium, and a monomeric amine which is capable of beingoxidized by said ceric salt and which is capable of initiating thepolymerization wherein said amine is the sole reducing agent.

12. A process comprising polymerizing a polymerizable monomeric compoundcontaining a polymerizably reactive CH =C group dissolved at leastpartially in an aqueous medium at a pH not greater than 3.5 and in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium and ethylene diamine wherein said diamine is thesole reducing agent.

13. A process comprising polymerizing acrylonitrile in an aqueous mediumat a pH not greater than 3.5 and in the presence of a ceric salt whichis soluble in at least one component of the reaction medium and ethylenediamine wherein said diamine is the sole reducing agent.

14. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound containing a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand a monomeric organic reducing agent which is capable of beingoxidized by said ceric salt and which is capable of initiating thepolymerization, wherein the only reducing agent is an organic reducingagent.

15. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound containing a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand a monomeric alcohol which is capable of being oxidized by said cericsalt and which is capable of initiating the polymerization wherein saidalcohol is the sole reducing agent.

16. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound containing a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand a monomeric polyhydric alcohol which is capable of being oxidized bysaid ceric salt and which is capable of initiating the polymerizationwherein said alcohol is the sole reducing agent.

17. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound containing a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand propylene glycol wherein said glycol is the sole reducing agent.

18. A process comprising polymerizing in an aqueous emulsion, styrene ata pH not greater than 3.5 and in the presence of a ceric salt which issoluble in at least one component of the reaction medium and propyleneglycol wherein said glycol is the sole reducing agent.

19. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound containing a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand a monomeric ketone which is capable of being oxidized by said cericsalt and which is capable of initiating the polymerization wherein saidketone is the sole reducing agent.

20. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound containing a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand a monomeric acetoacetic ester which is capable of being oxidized bysaid acid salt and which is capable of initiating the polymerizationwherein said acetoacetic ester is the sole reducing agent.

21. A process comprising polymerizing in an aqueous emulsion apolymerizable monomeric compound con taining a polymerizably reactive CH=C group at a pH not greater than 3.5 and in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand ethyl acetoacetate wherein said acetoacetate is the sole reducingagent.

22. A process comprising polymerizing in an aqueous emulsion,chloroprene at a pH not greater than 3.5 in the presence of a ceric saltwhich is soluble in at least one component of the reaction medium andethyl acetoacetate wherein said acetoacetate is the sole reducing agent.

23. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric compound containing a polymerizably reactive CH=C group in an aqueous medium at a pH not greater than 3.5 in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium and a polymeric organic reducing agent which iscapable of being oxidized by said ceric salt and which is capable ofinitiating the polymerization.

24. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric compound containing a polymerizably reactive CH=C group in an aqueous medium at a pH not greater than 3.5 in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium and a polymeric alcohol which is capable of beingoxidized by said ceric salt and which is capable of initiating thepolymerization.

25. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric c0n1- aaaa-ves r23 7 pound. containing apolymerizablyreactive CH =C group dissolved at least partially in anaqueous medium at a pH not greater than 3.5 in the presence of a cericsalt which is soluble in at least one component of the reaction mediumand a polymeric alcohol which is capable of being oxidized by said cericsalt and which is capable of initiating the polymerization.

26. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric compound containing a polymerizably reactive CH=C group dissolved at least partially in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a cellulosic materialwhich is capable of being oxidized by said ceric salt and which iscapable of initiating the polymerization.

27. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric cornpound containing a polymerizably reactive CH=C group dissolved at least partially in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and cellulose.

28. A process for preparing graft copolymers com prising polymerizing apolymerizable monomeric compound containing a polymerizably reactive CH=C group dissolved at least partially in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and cotton.

29. A process for preparing graft copolymers comprising polymerizingacrylonitrile dissolved in an aqueous medium at a pH not greater than3.5 in the presence of a ceric salt which is soluble in at least onecomponent of the reaction medium and cotton.

30. A process for preparing graft copolymers comprising polymerizing, inan aqueous emulsion, a polymerizable monomeric compound containing apolymerizably reactive CH =C group in an aqueous medium at a pH notgreater than 6.0 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polymeric alcohol whichis capable of being oxidized by said. ceric salt and which is capable ofinitiating the polymerization.

j 31. A process for preparing graft copolymers comprising polymerizing,in an aqueous emulsion, a polymerizable monomeric compound containing apolymerizably reactive CH =C group in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polyvinyl alcohol.

' 32. A process for preparing graft copolymers comprising polymerizing,in an aqueous emulsion, styrene at a pH not greater than 3.5 in thepresence of a ceric salt which is soluble in at least one component ofthe reaction medium and polyvinyl alcohol.

I 33. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric compound containing a polymerizably reactive CH=C group dissolved at least partially in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polymeric organicreducing agent which is capable of being oxidized by said ceric salt andwhich is capable of initiating the polymerization.

j 34. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric compound containing a polymerizably reactive 'OH==C group dissolved at least partially in an aqueous medium at a p'H notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction mediumand a polymeric ketone whichis capable of being oxidized by said ceric salt and which is capable ofinitiating the polymerization.

35. A process for preparing graft copolymers comprising polymerizingacrylonitrile dissolved in an aqueous medium at a pH not greater than3.5 and in the presence of a ceric salt which is soluble in at least onecomponent of the reaction medium and polyvinyl pyrrolidone.

36. A process for preparing graft copolymers comprising polymerizing apolymerizable monomeric compound containing a polymerizably reactive OH=C group dissolved at least partiallyin an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polymeric amine whichis capable of being oxidized by said ceric salt and which is capable ofinitiating the polymerization. I

37. A process for preparing graft copolymers comprising polymerizingacrylamide dissolved in an aqueous medium at a pH not greater than 3.5and in the presence of a ceric salt which is soluble in at least onecomponent of the reaction medium and polyvinyl amine.

38. A process for preparing graft copolymers comprising polymerizing, inan aqueous emulsion, a polymerizable monomeric compound containing apolymerizably reactive CH =C group in an aqueous medium at a pH notgreater than 6.0 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polymeric organicreducing agent which is capable of being oxidized by said ceric salt andwhich is capable of initiating the polymerization.

39. A process for preparing graft copolymers comprising polymerizing, inan aqueous emulsion, a polymerizable monomeric compound containing apolymerizably reactive CH =C group in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polymeric aldehydewhich is capable of being oxidized by said ceric salt and which iscapable of initiating the polymerization.

40. A process for preparing graft copolymers comprising polymerizing, inan aqueous emulsion, a polymerizable monomeric compound containing apolymerizably reactive CH ==C group in an aqueous medium at a pH notgreater than 3.5 in the presence of a ceric salt which is soluble in atleast one component of the reaction medium and a polymeric aldehydecomprising the copolymer of acrolein and a polymerizable monomericcompound containing a polymerizable CH =C group which is capable ofbeing oxidized by said ceric salt and which is capable of initiating thepolymerization.

41. A process for preparing graft copolymers comprising polymerizing, inan aqueous emulsion, methyl acrylate at a pH not greater than 3.5 and inthe presence of a ceric salt which is soluble in at least one componentof the reaction medium and a polymeric aldehyde comprising a copolymerof acrolein and styrene.

No references cited.

W it

UNITED STATES PATENT OFFICE CERTIFICATE OF CGRRECTION Patent No.2,922,768 January 26 1960 Guido Mino et al0 It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

In the grant, lines 1, 2 and 3 for "Guido Mino and Samuel Kaizerman, ofPlainfield, New Jersey read Guido Mino and Samuel Kaizerman, ofPlainfield, New Jersey, assignors to American Cyanamid Company, of NewYork N. Y. a corporation of Maine, line 12, for "Guido Mino and SamuelKaizerman, their heirs" read American Cyanamid Company, its successorsin the heading to the printed specification, line 6, for Guido Mine andSamuel Kaizerman, Plainfield, N. J." read Guido Mino and SamuelKaizerman, Plainfield, N. J. assignors to American Cyanamid Company, NewYork N., Y. a corporation of Maine column 1, line 26 for "is at least"read in at least line 59, for "invention to" read invention is column 4,line 40, for "celulose" read cellulose line 62, after ethanol" insert acomma; column 7, line 45, for "sulfomethylgulutaric" readsulfomethylglutaric column 9, line 24 for "where" read were column 17,line 32, for "performed" read preformed column 18, line 2, for "giveread gives column 21, line 37, for "gretaer read greLater-.

Signed and sealed this 28th day oflJune 1960.

(SEAL) Attest:

R AXLINE ROBERT c.. WATSON Attestlng Officer Conmissioner of Patents

1. A PROCESS COMPRISING POLYMERIZING A POLYMERIZABLE MONOMERIC COMPOUNDSCONTAINING A POLYMERIZABLY REACTIVE CH2=C< GROUP IN AN AQUEOUS MEDIUM ATA PH NOT GREATER THAN 3.5 IN THE PRESENCE OF CERIC SALT WHICH IS SOLUBLEIN AT LEAST ONE COMPONENT OF THE REACTION MEDIUM, AND AN ORGANICREDUCING AGENT WHICH IS CAPABLE OF BEING OXIDIZED BY SAID CERIC SALT ANDWHICH IS CAPABLE OF INITIATING THE POLYMERIZATION, WHEREIN THE ONLYREDUCING AGENT IS AN ORGANIC REDUCING AGENT.